The glycoglycerolipid 1,2-dipalmitoyl-3-(N-palmitoyl-6'-amino-6'-deoxy-α-d-glucosyl)-sn-glycerol is no inhibitor of the human Myt1 kinase

Fighting tubulin-targeting anticancer drug toxicity and resistance

Tubulin-targeting drugs, like taxanes and vinca alkaloids, are among the most effective anticancer therapeutics used in the clinic today. Specifically, anti-microtubule cancer drugs (AMCDs) have proven to be effective in the treatment of castration-resistant prostate cancer and triple-negative breast cancer. AMCDs, however, have limiting toxicities that include neutropenia and neurotoxicity, and, in addition, tumor cells can become resistant to the drugs after long-term use. Co-targeting mitotic progression/slippage with inhibition of the protein kinases WEE1 and MYT1 that regulate CDK1 kinase activity may improve AMCD efficacy, reducing the acquisition of resistance by the tumor and side effects from the drug and/or its vehicle. Other possible treatments that improve outcomes in the clinic for these two drug-resistant cancers, including new formulations of the AMCDs and pursuing different molecular targets, will be discussed.

Genome-wide CRISPR-Cas9 Screens Reveal Loss of Redundancy between PKMYT1 and WEE1 in Glioblastoma Stem-like Cells

To identify therapeutic targets for glioblastoma (GBM), we performed genome-wide CRISPR-Cas9 knockout (KO) screens in patient-derived GBM stem-like cells (GSCs) and human neural stem/progenitors (NSCs), non-neoplastic stem cell controls, for genes required for their in vitro growth. Surprisingly, the vast majority GSC-lethal hits were found outside of molecular networks commonly altered in GBM and GSCs (e.g., oncogenic drivers). In vitro and in vivo validation of GSC-specific targets revealed several strong hits, including the wee1-like kinase, PKMYT1/Myt1. Mechanistic studies demonstrated that PKMYT1 acts redundantly with WEE1 to inhibit cyclin B-CDK1 activity via CDK1-Y15 phosphorylation and to promote timely completion of mitosis in NSCs. However, in GSCs, this redundancy is lost, most likely as a result of oncogenic signaling, causing GBM-specific lethality.